Rupert Murdoch and his son James Murdoch could face jail for refusing to meet a select committee of MPs on phone hacking, but experts are divided on ancient parliamentary sanctions for non-British nationals. Photograph: Sang Tan/AP

Rupert Murdoch and his son James could face tough sanctions, including a jail term, if they repeatedly refuse to attend a select committee to answer questions over the phone-hacking scandal, MPs were told on Thursday although it is unclear whether ancient parliamentary sanctions could in practice be used.

But a leading constitutional expert has cast doubt on the idea that ancient constitutional powers could be used.

Trying to impose such infrequently exercised powers against a foreign national – in this case the Murdochs – is even less likely to be successful, according to Vernon Bogdanor, the former professor of government at Oxford University.

"My understanding is that as they are not British citizens no sanctions could be used against them," he said. "They could leave the country.

"A British national could, in theory, be fined or imprisoned [if they defied the summons]. The authority would be in the standing orders of parliament but my hunch is that [the sanctions to enforce it have] fallen into desuetude [disuse]."

John Whittingdale, chair of the culture scrutiny panel, said committees had taken such steps against individuals in the past, and they had complied. "I hope very much that the Murdochs will respond similarly," Whittingdale said.

MPs learned sanctions for contempt against the House could include a jail term as they demanded to know what could happen if the Murdochs also ignored the summons.

Commons leader Sir George Young said that if the pair were reported to the House for contempt they could face a public dressing down from speaker John Bercow or even imprisonment, although he stressed that he pointed out the sanctions "had not been used for some time".

Pressed on whether a further refusal to appear may be reported to the House as a breach of privilege, Young said: "A select committee can make a report to the House if it's believed a contempt has been committed.

"It is then a matter for you, Mr Speaker, to decide whether that should have precedence and it then gets referred to the committee on standards and privileges to take the matter further. A range of sanctions are available to the House for contempt. One includes you, Mr Speaker, admonishing somebody who appears at the bar, a responsibility I know you would discharge with aplomb. There are a range of other penalties including fines and imprisonment, but that has not been used for some time."

It concluded: "We suggest that the power to reprimand an offender in person at the bar of the House, though not used in recent times, should continue to be available.

"We recommend that measures to implement the recommendations of the joint committee that the House should lose its powers of imprisonment and should be given a statutory power to fine offenders be included in the draft privileges bill."

Erskine May, the handbook of parliamentary convention, is the relevant authority, a select committee official maintained. "If someone is in the UK's jurisdiction, they can be summoned," she said. "It means the summons can be delivered in person." Nationality is not relevant, she added.

The House of Commons is not believed to have fined anybody since 1666 and has not "committed anyone to custody", apart from temporarily detaining them, since the 19th century.

The last time the Commons attempted to reprimand anyone at the bar of the House was in 1957 was when the Sunday Express editor John Junor was criticised after offending MPs by publishing an editorial accusing them of abusing their petrol allowances. "Such a sanction would now appear high-handed," the recent standard and privileges committee report acknowledged.

In his evidence to the committee, Lord Nicholls warned the Commons that it lacked the necessary powers to deal with offenders. He said: "I find it very difficult to see how the House has any effective remedy here and I do wonder, going through with a full and thorough investigation, where it can lead. You can rap the editor of a newspaper over the knuckles and admonish him, which will not give him the loss of a wink's sleep, but there is nothing else, as I understand it, that, effectively, you can do."

The relevant passages of Erskine May are: "When a committee decides to summon a witness formally, the witness is summoned to attend the committee by an order signed by the chair. Failure to attend a committee when formally summoned is a contempt and if a witness fails to appear, when summoned in this manner, his conduct is reported to the House.

"… Foreign or Commonwealth nationals are often invited to attend to give evidence before committees ... There is no record of foreign or Commonwealth nationals resident (temporarily or permanently) in the United Kingdom being formally summoned, but on the analogy of the process in courts of law, there would appear to be no bar to their being summoned if they are present within the jurisdiction of parliament."